I have allways thought that toroidal transformers were better than any other common core type for amplifier power supplies. Lower impedance and less stray flux.
On the Onkyo website they suggest that this is not the case.
Your thoughts kind gentlefolk?
Regards WALKER

For the most state-of-the-art power delivery available-the custom-built toroidal transformer employed in the TX-DS989 is formed from a single strip of silicon steel, tightly wound in the form of a clock spring and wrapped in copper wire to form a silent, highly stable power supply virtually free of mechanical hum. The use of primary and secondary wiring around the entire core prevents air gaps, reducing magnetic flux, and making this very powerful, high-end unit 40% more efficient than conventional transformers.

High-Grade Isolated EI Transformers

Designed for efficient operation, even under high temperatures, these large transformers provide plenty of power reserves for today's multichannel digital sources.

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It seems to me that they are saying what everyone else is saying ...... Toroidal Transformers are the best most efficient, lowest noise transformers .........

this maybe true, but if you are going to get a custom EI core transformer of course the stats will be better ..... if u compare a custom EI core transformer with a custom toroidal transformer then things start to even up again but with the greater efficiency of toroids and less stray flux .......

" I keep saying "theoretically" as whether and to what
extent this will be true greatly depends on both
transformer materials and equally to its winding. If wound properly, so that a secondary ends on the spot where
it begins, if good quality rings are used and if good quality wire is used, then it will display all of its benefits to a considerable degree. In practice, unfortunately, I have seen far too many toroidal transformers which were poorly made, despite bold manufacturer claims.

Actually, you can check up on this rather easily. Using all necessary safety precautions, connect the transformer
to the mains, then connect your multi meter across the secondary and measure its quiescent current
consumption (the current it uses up with no load). Remember that by default, larger capacity transformer will use
more current than a smaller one, and in all cases, you are in the milliampere range, below 30."
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I've seen arguments pro and con for both EI and toroids. I wouldn't get too hung up on the point, myself. About the only reason I can see for really getting worked up is that toroids are somewhat less prone to interference. Even then, it's not that difficult to shield a transformer or, better still, arrange a remote power supply. Fringe benefits include getting any RF spray from the rectifier out of the way and more freedom to configure the circuit mechanically in a manner that suits you.

EI or laminated transformer is mostly use in power distribution, The advantage of this transformer is easy to mount and easy to wind. but if you consider the power efficiency EI is not efficient. toroid is more efficient than EI it is especially used in audio and computer electronics. beacause of high efficiency and free for magnetic interference.

Actually, you can check up on this rather easily. Using all necessary safety precautions, connect the transformer
to the mains, then connect your multi meter across the secondary and measure its quiescent current
consumption (the current it uses up with no load). Remember that by default, larger capacity transformer will use
more current than a smaller one, and in all cases, you are in the milliampere range, below 30."

And it's new meter time! I read this as you hanging a meter set to mA across the secondary. Poof!

What you meant was, measure the primary current with all secondaries unconnected. This, of course, should only ever be done by a qualified technician as you are directly on the mains now.